SLUUCJ6 November 2023
For proper operation, the top and bottom cells of the BQ76907 must be used. Cell count can be reduced by shorting the unused cell inputs from the next-to-top down. Cell count can be reduced for basic evaluation by shorting unused cells at the input terminal block. Follow the recommendations in the data sheet for which cells to short. Shorting at the input terminal block works for both operation with the cell simulator and cells, but can have some side effects in transient tests because it parallels the shorted resistors to the cell IC where the capacitor provides a signal path to the used input. See Figure 4-4 for an example of simple reduced cell configuration for 5 cells. For the best evaluation with reduced cells in a transient environment, short the VCx pins at the capacitor and remove the unused input resistor. When using the cell simulator, shorting the unused cell at the terminal block is still required to eliminate the simulated cell voltage. Shorting the cell inputs at the terminal block screw terminals is suggested since it will be apparent if the board is re-used for a different cell count. Table 4-1 shows configuration recommendations for reduced cell count.
Unused cell (numbered from bottom cell 1) | Short cell input terminals | Input resistor to remove | Replace capacitor with 0 ohm | IC inputs shorted |
---|---|---|---|---|
Cell 6 | CELL6 to CELL5 | R7 | C6 | VC6 to VC5 |
Cell 4 | CELL4 to CELL3 | R9 | C8 | VC4 to VC3 |